Power interrupting system for high voltage circuits



H. WUTZ July 12, 1966 POWER INTERRUPTING SYSTEM FOR HIGH VOLTAGE CIRCUITS Filed Jan. 14, 1963 INVENTORI Herbert Wutz y KW Y- United States Patent POWER INTERRUPTING SYSTEM VOLTAGE CIRCUITS Frankfurt am Main, Germany, assignor to Elektroindnstrie Aktiengesellschaft Voigt & Haeffner, Frankfurt am Main, Germany Filed Jan. 14, 1963, Ser. No. 251,439 Claims priority, application Germany, Jan. 13, 18962, C 25,994 15 Claims. (Cl. 317-35) This invention is concerned with power interrupting systems for interrupting electric high-voltage circuits.

Generally power circuit breakers are used for interrupting electric high-voltage circuits. There is, however, no power circuit breaker known which is capable of performing entirely satisfactorily on occurrence of various different interrupting conditions such as, interrupting major fault currents, or short-circuit currents, and inter rupting relatively small capactive line changing currents.

It is, therefore, the principal object of this invention to provide a power interrupting system for high-voltage circuits which lends itself equally well to various different interrupting conditions including interrupting major fault currents and interrupting relatively small capacitive line charging currents.

Another object of this invention is to provide composite circuit interrupting devices com-prising interrupting means which lend themselves particularly well to the interruption of major fault currents, and interrupting means which lend themselves particularly well to the interruption of relatively small capacitive line charging currents, in which interrupting devices both types of interrupting means are automatically controlled in such a fashion that the interrupting task at hand is performed by the interrupting means which is particularly adapted, or best suited, to perform that task, while the other interrupting means not particularly adapted and not best suited to perform that task does not take any part in it.

The interrupting performance of a'circuit interrupting device depends primarily upon the arc voltage which it generates during the arcing time and upon the rate of dielectric recovery of the arc gap following are extinction. These two qualities depend, in turn, upon the particular means used in any piece of circuit interrupting equipment for effecting interruption of the circuit to be interrupted. Because of their particular mechanism of circuit interruption circuit breakers using oil as an arc quenching medium, i.e. tank type oil circuit breakers and oil-poor circuit breakers, lend themselves well to the interruption of major fault currents including short-circuit currents. Such circuit breakers are generally not capable of effectively interrupting the capacitive currents which occur when disconnecting large capacitor banks, or on dropping long transmission or distribution lines. There is a tendency of restrikes and of build-up of dangerous overvoltages when oil circuit breakers are used for interrupting relatively small capacitive currents. Vacuum circuit breakers are not well suited for interruption of major fault currents because their ability to dissipate heat is relatively limited, and because interruption of very large currents involves the danger of generation of excessive amounts of metal vapors within the evacuated envelopes housing the contacts of vacuum circuit breakers. Vacuum circuit breakers have, however, performance characteristics which make this type of circuit breakers particularly suitable for interrupting relatively low substantially capacitive or leading currents. The same is also true in regard to axial air blast circuit breakers, i.e. such circuit breakers have also performance characteristics which make them particularly suited for interrupting relatively small capactive or leading currents.

FOR HIGH Herbert Wutz, Continental 3,260,896 Patented July 12, 1966 ice It is, therefore, another object of this invention to provide combinations of circuit breakers which use oil as an interrupting medium, such as tank type oil circuit breakers and oil-poor circuit breakers, or other circuit breakers having similar interrupting performance characterics, i.e. any kind of major fault current interrupting devices, and of vacuum circuit breakers, or axial air blast circuit breakers, or other circuit breakers having similar interrupting performance characteristics, i.e. any kind of capacitive current interrupting devices, which combinations of interrupting devices are under the control of a sensing means which deter-mines automatically which of the two associate-d devices ought to perform a specific interrupting task, and which of the two associate-d interrupting devices should be kept from performing a specific interrupting task for which it is not particularly well suited.

it is possible for the above mentioned ends to use combinations of major fault current interrupting devices, and of capacitive current interrupting devices, wherein the individual devices are either serially connected into the highvo-ltage circuit to be interrupted, or are connected in parallel into that circuit. In case of a series connection the circuit breaker which is particularly well suited to perform the required interrupting task is initially caused to form one or more serially related circuit interrupting breaks. Only after complete interruption of the circuit under consideration is the second circuit breaker or interrupting device caused to open. Since the circuit is interrupted by the time the contacts separate which form part of the circuit breaker or interrupting device which has not been required to perform a particular circuit interrupting task, that circuit breaker or interrupting device operates as a mere disconnect, interposing additional circuit insulation into a circuit previously interrupted by the operation of another piece of equipment.

Where two power circuit breakers, or other current interrupting devices, having different interrupting performance characteristics are arranged in parallel in the highvoltage circuit to be interrupted, the sequence of operation is different from the case of serially related power circuit breakers, or other current interrupting devices. In the case of parallel connection the circuit breakers or other current interrupting device not particularly suited for the interrupting task at hand is caused to open first, and thereafter the circuit breaker or other current interrupting device particularly suited for the interrupting task at hand is caused to open. Hence there is no voltage across the contacts of the circuit breaker or other current interrupting device which opens firs-t, the contacts of this circuit breaker or other circuit interrupting device being shunted at the time they part by the engaging contacts of the other circuit breaker or current interrupting device.

It is apparent from the foregoing that there is a predetermined sequence of opening of circuit breakers, or other current interrupting devices, in the aforementioned case of series connection and in the aforementioned case of parallel connection. The sequence is, however, different in both cases. In the case of serially connected circuit breakers, or other current interrupting devices, the device most appropriate for the interrupting task at hand opens first and the interrupting device less appropriate for the interrupting task at hand opens last. In the case of circuit breaker-s, or other current interrupting devices which are connected in parallel into the circuit to be interrupted the circuit breaker, or other current interrupting device, which is less appropriate for the interrupting task at hand opens first and it is followed by opening of the circuit breaker, or other current interrupting most appropriate for the interrupting task'at hand.

The brain determining which of the two possible sequences of circuit breaker operation ought to be adopted device, which isas the h1gh-voltage circuit in any specific instance vice.

erally be operatively related to other control equipment Which is on a lower voltage level. A current transformer and a potential transformer will generally be applied to energize the phase-angle sensing device. Where the circuit voltage is particularly high the phase-angle sensing device may be energized from the high-voltage line by the intermediary of a plurality of cascaded insulating transformers.

The phase-angle sensing device will generally take the form of a Tuma phase meter, or an equivalent type of phase-angle meter. Such an instrument comprises a fixed coil and two movable coils forming a single movable system pivoted in the field due to the fixed coil. Both movquadrature with the voltage. related phase-angle separable contacts forming part of a circuit breaker particularly adapted to interrupt relatively small capacitive currents. This circuit breaker may be a vacuum circuit breaker, or an axial air blast circuit breaker. The number of serially related cooperating separable contacts in each of the two circuit breakers depends primarily upon the system voltage related pairs of contacts l, l breakers. distribution and 2, 2 of the two circuit Both circuit breakers are shunted by a voltage controlling shunt extending across both cirdrawing the voltage distribution shunt includes a pair of might be replaced, if desired, by

serially related breaks between contact means 1, l and 2, 2. The equipotential conductor conductively interconnecting points between serially related pairs of contacts 1, 1 and 2, 2 of the two circuit breakers, or current interrupting the composite circuit breaker The current transformer 7 and the voltage current flowing in line ing in the phase-angle sensing system or phase meter 8, and the voltage transformer 9 energizes the voltage winding in the phase-angle sensing system or phase meter 8. Phase-angle sensing device 8 controls a auxiliary control valve, or pilot valve, pulse of air under pressure to the change-over valve 11 to indicate a tripping means such as a circuit breaker trip- Tripping means 12 may be energized either given opening command or in gized a tripping valve forming an integral part of tripping means 12; is opened and admits air under pressure to the changeover valve system 11. The latter has two positions. In one of the two positions air under pressure is admitted sequentially to the pneumatically operated control valves 14, 13. The sequence is reversed if change-over valve 11 opening the left interrupting control Valve 14.

If a manual tripping impulse is sent to the tripping means 12, or if the latter is energized by the action of a fault current responsive relay, the current flowing in line 4 should be interrupted by the circuit breaker comprising the serially related pairs of contacts 1, 1, and the circuit of serially related contacts path through the left circuit breaker. If a capacitive or leading current flows through line 4 the phase-angle sensbreaker including contact means 2, 2 to rent interrupting position giving circuit breaker including contact its capacitive curprecedence to the right means 1, 1. If change- S in the performance of an interrupting taks for not well suited.

Change-over valve 11 is normally held in the position giving opening precedence to the left circuit breaker, or biased to that position. The position of change-over valve 11 is changed to the position giving opening precedence to the right circuit breaker comprising contact means 1, 1 only upon occurrence of a capacitive current in line 4. Thus there is no delay in interrupting major fault currents or short circuit currents, the system being always ready to perform this paramount duty, and only changing to the performance of its duty of interrupting relatively small capacitive currents when an occasion to perform such particular duty arises.

Since the circuit breaker comprising contact means 2, 2 is, or may be, capable of interrupting load currents and small overload currents in addition to interrupting capacitive currents, the right circuit breaker comprising contact means 1, 1 may be relieved of its task of interrupting load and small overload currents. In other words, the right circuit breaker comprising contact means 1, 1 may be designed for the sole purpose of interrupting major fault currents, and thus its design may be considerably simplified. 'Under such conditions the change-over valve 11 may normally be held in the position giving precedence to the opening operation of the right circuit breaker comprising contact means 1, 1 and be shifted on occurrence of a major fault current by an appropriate sensing device responsive to a parameter of the current flowing in line 4 to the opposite opening sequence position thereof.

It will be seen from the foregoing that the particular embodiment of the invention which I have described presupposes the presence of a pneumatic control and of a pneumatic contact opening system for the major fault current circuit breaker and for the capactive current circuit breaker. The presence of such a control system and such a contact opening system has been assumed to better illustrate the invention, but the invention is not limited to the presence of such a control system and contact opening system. Both circuit breakers might be controlled by a substantially conventional electric circuit breaker control system which may be combined with two appropriate fluid motors to effect sequential separation of pairs of cooperating contacts in either of both circuit breakers. In that instance the change-over valve 11 has to be replaced by a change-over switch having two positions governing the sequence to be given to the opening operations of the two circuit breakers. Such a change-over switch may be, in turn, under the control of phase-angle sensing instrument 8.

Having disclosed a preferred way of carrying my invention into effect, it is desired that the same not be limited to the particular arrangement of parts disclosed. It will be obvious to any person skilled in the art that many modifications and changes may be made without departing from the broad spirit and scope of the invention. Therefore it is desired that the invention be interpreted as broadly as possible and that it be limited only as required by the prior state of the art.

I claim as my invention:

1. A power interrupting system for interrupting electric high-voltage circuits comprising in combination:

(a) an electric high-voltage circuit;

(b) a pair of power circuit breakers having different interrupting performance characteristics included in said circuit, said pair of circuit breakers including a first circuit breaker particularly adapted'to interrupt major fault currents and said pair of circuit breakers including a second circuit breaker particularly adapted to interrupt relatively small currents including capacitive currents;

(c) tripping means for initiating opening of said pair of circuit breakers;

(d) change-over means having two positions for selectively determining the sequence of opening of said which it is first circuit breaker and of said second circuit breaker in response to said tripping means; and (e) sensing means under the control of the current flowing in said circuit for operating said changeover means in response to a parameter of said current. 2. A power interrupting system for interrupting electric high-voltage circuits comprising in combination:

(a) an electric high-voltage circuit; (b) a plurality of power circuit breakers having different interrupting performance characteristics included in said circuit; I (c) tripping means for initiating opening of said plurality of circuit breakers; (d) phase-angle sensing said circuit for determining the and (e) means responsive to said tripping means and also responsive to said phase-angle sensing means for establishing a predetermined sequence of opening of said plurality of power circuit breakers in response to the phase-angle prevailing in said circuit. 3. A power interrupting system as specified in claim 2 wherein said plurality of circuit breakers includes a circuit breaker wherein oil is used as an arc-quenching memeans operatively related to phase-angle therein;

' dium and a vacuum circuit breaker.

4. A power interrupting system as specified in claim 2 wherein said plurality of circuit breakers includes a circuit breaker wherein oil is used as an arc-quenching medium and an axial air blast circuit breaker.

5. A power interrupting system as specified in claim 2 wherein said phase-angle sensing means is arranged at substantially the same potential as said high-voltage circuit.

6. A .power interrupting system for interrupting electric high-voltage circuits comprising in combination:

(a) an electric high-voltage circuit;

(b) a plurality of break-forming current interrupting devices having different interrupting performance characteristics included in said circuit;

(c) tripping means for initiating opening of said plurality of interrupting devices;

((1) a current transformer operatively related to said circuit;

(e) a potential transformer operatively related to said circuit;

(f) a phase-angle meter operatively related to said current transformer and to said voltage transformer to indicate the phase-angle in said circuit; and

(g) means responsive to said tripping means and also responsive to said phase-angle meter for establishing a predetermined sequence of opening of said plurality of interrupting devices in response to the phase-angle prevailing in said circuit.

7. A power interrupting system for interrupting electric high-voltage circuits comprising in combination:

(a) an electric high-voltage circuit;

(b) a pair of break-forming pneumatically operated current interrupting devices having different interrupting performance characteristics included in said circuit;

(c) a pair of pneumatically operated control valves each operatively related to the contact separating means of one of said pair of interrupting devices;

((1) tripping means for initiating opening of said plurality of interrupting devices;

(e) a tripping valve under the control of said tripping means for admitting air under pressure to said pair of control valves in response to operation of said tripping means;

(f) a pneumatically operated change-over valve supplied with air under pressure from said tripping valve and admitting air under pressure to said pair of control valves, said change-over valve including means for varying the sequence of admission of air under pressure to each of said pair of control valves;

tric high voltage circuits (g) phase-angle sensing means operatively related to said circuit; and

(h) an auxiliary control valve under the control of said phase-angle sensing means for admitting air under pressure to said change-over valve to operate said change-over valve in response to the phaseangle prevailing in said circuit.

8. A power interrupting system for interrupting electric high voltage circuits comprising in combination:

(a) an electric high-voltage circuit;

(b) a pair of break-forming current interrupting devices having different interrupting performance characteristics arranged in parallel in said circuit, said pair of interrupting devices including a first interrupting device particularly adapted to interrupt device and of said first interrupting device; and (e) sensing means under the control of the current flowing in said circuit for operating said control means in response to a parameter of said current. 9. A power interrupting system for interrupting electric high-voltage circuits comprising in combination:

(a) an electric high-voltage circuit; (b) a pair of break-forming current interrupting devices having different interrupting current interrupting device;

(c) tripping means for initating opening of said pair of interrupting devices;

(d) control means having a first position and a second position and being adapted when in said first position thereof to cause sequential opening of said capacitive current interrupting device and of said major fault current interrupting device in response to operation of said tripping means, and said control means being adapted when in said second position thereof to cause sequential opening of said major fault current interrupting device and of said capacitive current interrupting device in response to operation of said tripping means; and

(e) phase-sensing means for determining the phaseangle in said circuit, said sensing means being operatively related to said control means to shift said control means from said first position thereof to said second position thereof upon occurrence of a capacitive current in said circuit.

10. A power interrupting system as specified in claim 9 wherein said capacitive current interrupting device is a vacuum circuit breaker.

A power interrupting system as specified in claim 11. 9 wherein said capacitive current interrupting device is an axial blast air blast circuit breaker.

12. A power interrupting system for interrupting eleccomprising in combination: (a) an electric high-voltage circuit;

(b) a pair of break-forming current-interrupting devices having different interrupting performance characteristics arranged in parallel in said circuit, said interrupting devices including a major fault current interrupting device and a capacitive current interrupting device, and each of said pair of interrupting devices including serially related pairs of separable contacts to form series breaks upon separation of said pairs of contacts;

(0) equipotential conductor means conductively interconnecting points between serially related pairs of contacts of said pair of interrupting devices;

(d) voltage distribution controlling shunt means extending across said pair of interrupting devices and conductively connected to said equipotential conductor means;

(e) tripping means for initiating opening of said pair of interrupting devices;

(f) control means having a first position and a second position and being adapted when in said first position to cause sequential opening of said capacitive current interrupting device and of said m-ajor fault current interrupting device in response to operation of said tripping means, and said control means being adapted when in said second position thereof to cause sequential opening of said major fault current interrupting device and of said capacitive current interrupting device; and

(g) phase-sensing means adapted to sense the phase angle in said circuit operatively related to said control means to shift said control means from said first position thereof to said second position thereof upon occurrence of a capacitive current in said circuit.

13. A power interrupting system for interrupting electric high-voltage circuits comprising in combination:

(a) an electric high-voltage circuit;

(b) a pair of break-forming current interrupting devices having different interrupting performance characteristics arranged in parallel in said circuit, said pair of interrupting devices including a major fault current interrupting device and a capacitive current, interrupting device;

(0) tripping means for initiating opening of said pair of current interrupting devices;

((1) control means having a first position and a second position and being adapted when in said first position thereof to cause sequential opening of said capacitive current interrupting device and of said major fault current interrupting device in response to operation of said tripping means, and said control means being adapted to cause when in said second position thereof sequential opening of said major fault current interrupting device and of said capacitive current interrupting device;

(6) a current transformer operatively related to said circuit;

(f) a potential transformer operatively related to said circuit; and

(g) a phase-angle meter connected to said current transformer and to said potential transformer to indicate the phase-angle in said circuit, said meter being operatively related to said control means to shift said control means from said first position thereof to said second position thereof upon occurrence of a capacitive current in said circuit.

14. A power interrupting system for interrupting electric high-voltage circuits comprising in combination:

(a) an electric high-voltage circuit;

(b) a pair of break-forming current interrupting devices having different performance characteristics arranged in parallel in said circuit, said pair of current interrupting devices including a first current interrupting device particularly adapted to interrupt major fault currents and said pair of current interrupting devices including a second current interrupting device particularly adapted to interrupt relatively small currents including capacitive currents;

(c) tripping means for initiating opening of said pair of current interrupting devices;

(d) variable means for controlling and changing the ranged in parallel in said circuit, said pair of current interrupting devices including a first current interrupting device particularly adapted to interrupt major t-ault currents and said pair of current interrupting devices including a second current interrupting device particularly adapted to interrupt relatively small currents including capacitive currents;

(c) tripping means for initiating opening of said pair of current interrupting devices;

(d) variable means for controlling and changing the sequence of opening of said pair of current interrupting devices, s-aid variable means being normally maintained in a position causing opening of said first current interrupting device to precede opening of said second current interrupting device; and

(e) sensing means affected by the flow of current in said circuit adapted to vary said sequence controlling and changing means to reverse the sequence of opening of said first current interrupting device and of opening said second current interrupting device.

References Cited by the Examiner UNITED STATES PATENTS 12/1918 Chulbb 317--11 3/1941 Kesselring 317-11 X MILTON O. HIRSHFIELD, Primary Examiner. SAMUEL BERNSTEIN, Examiner.

I. D. TRAMMELL, Assistant Examiner. 

1. A POWER INTERRUPTING SYSTEM FOR INTERRUPTING ELECTRIC HIGH-VOLTAGE CIRCUITS COMPRISING IN COMBINATION: (A) AN ELECTRIC HIGH-VOLTAGE CIRCUIT; (B) A PAIR OF POWER CIRCUIT BREAKERS HAVING DIFFERENT INTERRUPTING PERFORMANCE CHARACTERISTICS INCLUDED IN SAID CIRCUIT, SAID PAIR OF CIRCUIT BREAKERS INCLUDING A FIRST CIRCUIT BREAKER PARTICULARLY ADAPTED TO INTERRUPT MAJOR FAULT CURRENTS AND SAID PAIR OF CIRCUIT BREAKERS INCLUDING A SECOND CIRCUIT BREAKER PARTICULARLY ADAPTED TO INTERRUPT RELATIVELY SMALL CURRENTS INCLUDING CAPACITIVE CURRENTS; (C) TRIPPING MEANS FOR INITIATING OPENING FOR SAID PAIR OF CIRCUIT BREAKERS; (D) CHANGE-OVER MEANS HAVING TWO POSITIONS FOR SELECTIVELY DETERMINING THE SEQUENCE OF OPENING OF SAID 